Driving method for discharge lamp, driving device for discharge lamp, light source device, and image display apparatus

A driving device for a discharge lamp, comprising:

• an alternating current supply section configured to supply two electrodes of the discharge lamp with an alternating current having a frequency, the alternating current comprising a plurality of modulation periods with each modulation period including a plurality of terms;
• and
• a frequency switching section configured to vary the frequency of the alternating current supplied by the alternating current supply section,
• wherein the frequency switching section varies, in response to a predetermined condition being satisfied, the frequency of the modulation periods such that the variation in the frequency between two temporally consecutive terms in the modulation period is larger than the variation in the frequency between two temporally consecutive terms in the modulation period when the predetermined condition fails to be satisfied.

A light source device comprising:

• a discharge lamp;
• an alternating current supply section configured to supply two electrodes of the discharge lamp with an alternating current to light the discharge lamp, the alternating current comprising a plurality of modulation periods with each modulation period including a highest frequency term and a lowest frequency term;
• and
• a frequency switching section configured to vary a frequency of the alternating current supplied by the alternating current supply section non-monotonically between the highest frequency term and the lowest frequency term in response to a predetermined condition being satisfied.

An image display apparatus comprising:

• a discharge lamp as alight source configured to display an image;
• an alternating current supply section configured to supply two electrodes of the discharge lamp with an alternating current to light the discharge lamp, the alternating current comprising a plurality of modulation periods with each modulation period including a highest frequency term and a lowest frequency term;
• and
• a frequency switching section configured to vary a frequency of the alternating current supplied by the alternating current supply section non-monotonically between the highest frequency term and the lowest frequency term in response to a predetermined condition being satisfied.